470 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1962 



Figure 8. — A-C, E, F, Platasierias latiradiata (Somasteroidea); D, Luidia (Asteroldea, 

 Platyaslerida), cross section of extreme armtip. For explanation, see text. Abbrevia- 

 tions: 1, ambulacral ossicle; 2, first virgalium (V-1, or adambulacral ossicle); 3, third 

 virgalium (V-3, or inferomarginal ossicle); 4, superomarglnal paxilla; 5, second virgalium 

 (V-2, or superambulacral ossicle); 6, dorsal surface of arm; 9, fourth virgalium (V-4, or 

 inferomarginal radiole); 11, adductor of ambulacral ossicles. 



